Simulation Lag Fix

This is an update to simmythesim's Simulation Lag Fix for the latest version of the game.
It was also previously maintained by Xerox on Mod The Sims, but they no longer are keeping it updated.

I have been updating the mod for quite some time now via the comments on Xerox's MTS page. But decided I should post it here so I do not forget to update it in the future.

I have not changed anything from the original mod, I simply just updated the python code and patched it for the most recent update for The Sims 4.

If you use MC Command Center to adjust the "Game Time Speed" in the game manually, DO NOT use this mod. 
By Manually I mean: "MCCC > MCCC Settings > Gameplay Settings > Game Time Speed" This should not be adjusted in MCCC if you use Sim Lag. Leave it alone at the defaulted to 25 in MCCC. 

If you use MCCC but do not adjust the "Game Time Speed", you are fine. 

Compatible with TurboDrivers Simulation Unclogger. 
These mods do two completely different things, and I highly recommend grabbing TurboDrivers mod to use with Sim Lag Fix.

What does this mod do?

"This mod alters the game's time speeds so that sim autonomy does not cause massive simulation lag in instances where there are many autonomy requests."

This should eliminate, or at the very least, alleviate, the following problems:

  • Sims head bobbing
  • Sims doing nothing for a few hours
  • time slowing down on speed 3
  • time going back to the past

Mod Explanation

This seems rather basic, but there's a video showing a scientist experimenting in GTW without the mod:

Here it is with the mod installed:

Everything runs much more frequently now, preventing the "bobbing head" effect. I haven't experienced any time rolling-back since I made the mod!


This mod overrides the following python functions:
  • time_service.TimeService.start
  • time_service.TimeService.update
and overrides the following XML:

  • Clock - E81E51B398141F79
  • Time_Service - 2BE55516548A9522


Unzip the mod files into your mods folder.
Make sure script mods and custom content are enabled in your game!

If you have bugs after updating normally, follow these steps:

1. Remove the previous version of Sim Lag Fix and Clear Your Cache.
2. Start your game with Sim Lag Fix removed, progress in your save 1-2 sim days.
3. Save your game, then close it.
4. Install the new version of Sim Lag Fix, and enjoy!

Additional Credits:

simmythesim for the original mod & page description


NOTE: If you have any issues with this mod, or want to report any bugs please do so in Discord under the #bug_reports section. This is the best way to get quick and easy 1 on 1 help. 


  1. I am so glad you have taken over love this mon

  2. Thank you! You are a saint!! My game is unplayable without this mod

  3. I'm so happy this mod exists! ♥

  4. There are many of us who are so very appreciative of your work and efforts to make the Sims 4 more playable. Thanks so much!

  5. Hi, I appreciate this mod so much, thank you for updating it! Love from Germany.

  6. Thank you so much for fixing and sharing this!

  7. Love how you keep this up to date, noticed an update just today :D

  8. Thanks for keeping this up to date

  9. Hail!
    One quick question, does this mod do the same as the Simulation Unclogger from Turbodriver, or they adress different problems, and would be usefull to be used together.

    1. Good question! The answer is yes, they do two different things and are compatible with each other.

  10. Love your mods, and keep up the good work.

  11. Can this mod be used with MCC? I have mcc adjusting game time speed so thought it was worth asking.

    1. If you adjust game time speed with MCCC this will not work. You would have to pick which mod you want to adjust game speed. This mod does however adjust time differently then MCCC.

    2. Hello! Thanks for keeping this mod alive and well! But I have a couple of questions. First, by "Adjusting game speed" via MCCC, do you mean the "MCCC > MCCC Settings > Gameplay Settings > Game Time Speed" command that defaults at 25? If so, should we change that default speed to 17, like you write under the console command above, or leave it at it's default 25 value? Second, if we have set our MCCC to properly NOT adjust game time (considering your answer to question 1) should we still use the console command above? And will we need to do this command each time we start up our game client? Sorry for all the questions, I'm fairly new and just want stuff to work well xD I really do appreciate you having this mod available, thank you!

    3. That is exactly the option I mean. Do not adjust that value with MCCC. It will cause funky things to happen with Sim Lag installed.

      The cheat listed in the patch from October 3rd is a testing cheat. This is not something that must be done, but is optional and does not conflict with the code that Sim Lag alters directly.
      I have been testing it in my personal game to see how it affects Sim Lag. Personally, if you do not want to do trial and error, just do not worry about using the cheat. I will update the post to be a little more clear on that. :) Always happy to help, it is easier to get help in my Discord tho! Be sure to stop by sometime.

  12. sooooooo much thank you for this mod!!!

  13. Replies
    1. Yes, 1.58.69 was just minor bug fixes and no actual XML changes. :)

  14. is this still usefull in 2020?

  15. Thanks for your work, this has improved my game a lot!

  16. Thank you this has helped my game alot! When was this last updated?

    1. It was updated for the last patch. You can always see what my mods have been updated to on the right side of the page under "Game Mods Notice".

  17. Hi,

    when will it be possible to get the update to Version Since this upgrade there are frequent bugs that Sims freeze and do not move at all. Resulting in a complete loss of control of the game. Thanks.

    1. There already is an update. Check the downloads or come to my Discord for announcements for updates...

  18. Thank you so much! It's great.

  19. Thanks Man! Hope you continue with this great work!

  20. so beautiful,thank you very much


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I will not answer help/bug report questions in comments.
They will be ignored.